Patio umbrellas and market umbrellas are frequently used to provide shade outdoors, and are also used for various applications indoors in homes, retail shopping centers, hotels, restaurants, and other locations. Patio umbrellas and market umbrellas are similar in form and function. In this text, patio umbrellas and market umbrellas are referred to as conventional patio umbrellas.
Conventional patio umbrellas are comprised of a mast that is generally 8 feet or more in height, a canopy having a diameter between 6 feet and 12 feet and made of fabric or other foldable material affixed at its center to the upper end of the mast, a plurality of ribs evenly spaced around the mast circumference, whereby one end of each rib is pivotally attached to the upper end of the mast under the canopy and the opposite end of each rib is attached to the canopy perimeter, and a plurality of levers whereby one end of each lever is pivotally attached to one of the ribs and the opposite end of each lever is pivotally attached to a yoke. The yoke forms a ring applied on the circumference of the mast and is movable along a portion of the length of the mast. Conventional patio umbrellas have a yoke operating means to cause the yoke to move up and down the mast to apply and reduce force on the levers and thereby the ribs causing the canopy to open and close. Yoke operating means of conventional patio umbrellas vary in configuration, however all require human effort to operate. An example of a yoke operating means is a mechanism comprising a hand operated winch, rope and pulley drivingly engaged with the yoke. Another example of a yoke operating means comprises one or more hand operated ropes over pulleys drivingly engaged with the yoke. Another example of a yoke operating means comprises manual hand lifting and lowering of the yoke, or other means requiring human effort to cause the yoke to move up and down the mast and thereby open and close the canopy.
When in use, the mast of a conventional patio umbrella stands in a vertical position with the canopy at the upper end and with its lower end installed through a hole in the center of a table and supported, or the mast can be supported by a structure in a freestanding position. In its closed position the canopy is folded compactly around the circumference of the mast. The canopy can be made to open when the yoke operating means forcibly moves the yoke toward the upper end of the mast thereby forcing the levers against the ribs causing the ribs to pivot upwards on mast attachment points and thereby lifting the canopy causing it to spread up and away from the mast to an open position. The canopy is retained in the open position by the yoke operating means or other retention means. In its open position the canopy can be made to close when the yoke operating means causes the yoke to move away from the upper end of the mast thereby reducing the lever force against the ribs and whereby gravity causes the ribs to pivot downward on mast attachment points and the canopy collapses and folds compactly around the circumference of the mast.
Various mechanisms have been invented to motorize patio umbrellas, however these involve modifications to the working parts of a conventional patio umbrella, or a completely new patio umbrella design. As described in the art, motorized patio umbrellas are only available as a factory equipped mechanism constructed by patio umbrella manufacturers. Patents disclosing such mechanisms include U.S. Pat. No. 6,612,713 to Kuelbs, U.S. Pat. No. 6,543,464 to Grady, U.S. Pat. No. 6,182,917 to Lai, and others.
Factory motorized patio umbrellas are growing in popularity because they offer luxury, convenience, and are easier to operate than conventional patio umbrellas. However, to enjoy these benefits requires the purchase of a new and expensive patio umbrella.